Field emergence potential of seeds is the most important practical aspect of seed quality as it decides the performance of the resultant crop. Among the treatments, fortified seeds coated with T
7 (Fortified seed – Polymer @ 3ml/kg + Carbendazim @ 2 g/kg + imidachloprid @ 2 ml/kg +
Tichoderma viride @ 4 g/kg+
Azospirilum @ 40 g /kg), improved the field emergence over untreated control by 13.7 and 22.2 per cent for 2013 and 2014, respectively (Table 1). The T
7 treated seeds took minimum days (65 and 70 days for 2013 and 2014 respectively) for 50 per cent flowering compared to untreated control (76 and 79 days for 2013 and 2014 respectively) (Table 1). Increased plant growth and yield were due to KCl fortification of seed which is favourable for the development of plasma colloids. Potassium has a prevalent action in plants and is involved in maintenance of ionic balance in cell and bounds ironically to enzyme pyruvate kinase which is essential in respiration and carbohydrate metabolism
(Aisha et al., 2007). The beneficial effect might be due to polymer and nutrients. The improvement in field emergence could also be ascribed to activation of cells, which results in the enhancement of mitochondrial activity leading to the formation of more high energy compounds and vital bimolecules, which were made available during the early phase of germination (
Kavitha, 2002).
Duan and Burris (1997) reported that higher germination and field emergence percentage could be seen in polymer coated sugar beet seeds, and it was mainly due to increase in the rate of imbibitions where the fine particles in the coating acts as “wick” or moisture attracting material or perhaps to improve germination. Polymer coating increased the absorption of water, gases, micronutrients and the activity of hormones which help rapid and quick seedling emergence, faster growth and early panicle emergence in paddy.
In cotton pest and disease is a severe problem and may cause yield reduction. Pest and disease incidence was less in T7 treated seeds (4 and 3.79% for 2013 and 2014 respectively) compared to untreated control seed (6.8 and 9.5% for 2013 and 2014 respectively) (Table 1). Polymer coating of seed improve physical properties of the seed and provide protection from biological enemies
(Bennett et al., 1992). This might be due to the presence of polymer which improved the resistance of seeds towards pest and disease in the much warranted juvenile stage, besides improving seedling vigour.
Chen et al., (2004) reported that corn seeds coating with super absorbent polymer played an important role in improving the growth and inducing the activity of pest and disease resistance-related enzymes in seedlings for its keeping water ability and it would be beneficial to the pest and disease control.
The yield attributes
viz., plant population at maturity stage/plot, number of sympodial branches /plant, number of bolls/plant, kapas yield/plant (g), kapas yield/plot (kg) and seed yield/ plant (g) were found to be significant. Among the treatments, T
7 (Fortified seed- Polymer @ 3 ml/kg + Carbendazim @ 2 g/kg + imidachloprid @ 2 ml/kg +
Tichoderma viride @ 4 g/kg +
Azospirilum @ 40 g /kg), recorded higher plant population at maturity stage/plot, number of sympodial branches /plant, number of bolls/plant, kapas yield/plant (g), kapas yield/plot (kg) and seed yield/ plant (g). The per cent increase over control was 31.8, 7.5, 18.9, 18.6, 12.6 and 18%, respectively for 2013 and 14.1 plant population at maturity stage/plot, 16.6 number of sympodial branches /plant, 34.2 number of bolls/plant, 19.3 kapas yield/plant (g), 39.8 kapas yield/plot (kg) and 13.6 seed yield/ plant (g) for 2014 (Table 2, 3 and Fig 1). The reason for the increased yield might be due to the increased photosynthetic efficiency through stabilization of chlorophyll, higher production of photosynthates resulting in increased translocation of organic material from the source to sink in the treated plants. Similar findings are also reported by
Chachalis and Smith (2001) in Soybean,
Sabir- Ahamed (2003) in maize and
Rana et al., (2001) in Indian mustard,
Rajasekaran (2004) in brinjal,
Vinitha (2006) in tomato,
Marimuthu (2007) in rice and
Vegula (2008) in maize. Yield increase due to polymer coating was reported by
Chikkana et al., (2000) in groundnut;
Senhur Kumaran et al., (2001) in tomato,
Nisha Chandran (2003) in MCU 5 cotton,
Sherin (2003) in maize,
Saritha Devi (2004) in sorghum,
Praveena (2005) in cotton and
Natesan (2006) in blackgram and
Shakuntala et al., (2010) in sunflower hybrid.
The yield increase could be attributed to the presence of inoculants, protectants, nutrients and polymer in the coating treatment. Growth promotion by
Trichoderma which is attributed to solublization and sequestration of many plant nutrients such as P, Mn, Fe and Zn and supply to the plants, which in turn into increased plant growth
(Lal et al., 2013). The increased yield was attributed to increase in plant stand and plant establishment with suppression of seed borne pathogens. Inhibition of the activity of the pathogen resulted in more total dry matter production which facilitates more availability of photosynthates for sink and ultimately resulted in increased yield. Similar findings were observed by Sunil
Kumar et al., (2009) in soybean. Azospirillum inoculation is mainly attributed to increased growth due to increase root biomass and accumulation of nitrogen and the production of gibberellins and cytokinin like substances which promote the growth of the seedlings. There are many reports that seed inoculation of Azospirillum, increased biomass and grain yield (
Woodard and Bly, 2000) increased cob length and cob weight
(Cavallet et al., 2000).
